What is being cached in the stale compilation cache?

Julia used to do this a lot in 1.0, its mostly solved since 1.3 IIRC, because we have multiple caches.

[ Info: Recompiling stale cache file /Users/oxinabox/.julia/compiled/v1.0/Revise/M1Qoh.ji for Revise [295af30f-e4ad-537b-8983-00126c2a3abe]

Is it JIT compilation of methods used?
Or is it precompilation stuff?

From what I understand, it is lowered code and inference results.

From Analyzing sources of compiler latency in Julia: method invalidations

For example, julia creates “precompile” ( *.ji ) files to speed up package usage. Currently, it saves type-inferred but not native code to its precompile files.